Acoustical and thermal insulating fibrous glass products have been manufactured for many years. Such manufacturing typically involves a process which comprises attenuating the fibers, for example, with a rotary device, to produce a downwardly falling stream of fibers. During their downward flow path, a binder is sprayed onto the glass fibers and the sprayed fibers then collected on a conveyor in the form of a blanket. This blanket is then heated so as to bind the fibers with the binder. Typically, in the past, such binders were themosettable resins. Such resins have many desirable properties, but, unfortunately, they are relatively expensive.
In German Offenlegungsschrift No. 28 42 355, a chemically modified asphalt is taught. This chemically modified asphalt is the reaction product of asphalt, a vinyl aromatic monomer, for example, styrene, and a rubber. This publication teaches that when glass fibers are coated with such a chemically modified asphalt, the material can be insolubilized by an optional heating step carried out at temperatures in the range of about 200.degree. to 500.degree. F. (93.degree. to 260.degree. C.). Unfortunately, however, it will be appreciated that because of the chemical reaction which is needed to obtain the chemically modified asphalt, the costs of that material are increased relative to conventional asphalt which has not been chemically modified and, additionally, the materials used, i.e., the rubber and styrene, are commonly more expensive than asphalt. Consequently, the obtainment of the insolubilized chemically modified asphalt coating is penalized because of cost considerations.